1. 25 cm3 of a solution of 0.1 moldm-3 NaOH reacts with 50 cm3 of a solution of hydrochloric acid. What is the molarity of the acid? 2. 25.0 cm3 of a 0.10 moldm-3 solution of sodium hydroxide was titrated against a solution of hydrochloric acid of unknown concentration.
We made this inference due to our slope of each of the graphs. Given the mole ratios, the slope of our newer lab, comparing H2 to moles of Mg, should’ve been a slope of 1. But our first point skewed our results giving us an actual slop of 0.7, which was short from a more accurate result. And given our results last week, we concluded that our titration method was more accurate than our crystallization method due to the basically perfect slope of 2.0018 which is very close to the theoretical slope of 2. 5.
Determine the percent yield of this reaction, showing all steps of your calculation. (3 points) heoretical yield of H2 gas: (1.156 x 10^-3 moles)(1 mole H2/ 1 mole Mg) = 1.156 x 10^-3 moles Theoretical mass: (1.156 x 10^-3 moles)(2.02 g/mole) = 2.335 x 10^-3 g Using ideal gas law: P = (1.1 atm)(760 torr / 1 atm) - 19.8 torr = 816.2 torr V = 0.026 L T = 295 K Solve for n: n = PV/(RT) n = (816.2 torr)(0.026
Practice Test 4 –Bus 2023 Directions: For each question find the answer that is the best solution provided. There is only one correct answer. 1. For a sample size of 30, changing from using the standard normal distribution to using the t distribution in a hypothesis test, a. will result in the rejection region being smaller b. will result in the rejection region being larger c. would have no effect on the rejection region d. Not enough information is given to answer this question. ANSWER: a -recall that all the t-values are larger than the z-values so it makes it more difficult to reject the null.
This reaction can be summed up using the following formula: 5Fe2++8H++MnO4- →5Fe3++Mn2++4H2O After standardization, the potassium permanganate solution is then titrated with 3 different magnesium oxalate solutions. To find the concentration of the C2O42- the balanced net ionic redox reaction formula is used: 5C2O42-+16H++2MnO4- →10CO2+2Mn2++8H2O It is important to note the addition of sulfuric acid (9M H2SO4) in performing this experiment because of the following reasons: 1) Sulfuric acid keeps the iron (II) from air oxidizing into iron (III) 2) Sulfuric acid keeps the iron (II) from hydrolyzing into Fe(OH)2 3) Sulfuric
The total risk score is 4.14, the greatest relative or standardized difference between pretest and 3 month outcomes. This t ratio has a statistical significance of 0.05 - the least acceptable value for statistical significance. Also the larger the t ratio, the smaller the observed p value and increased odds of being able to reject the null hypothesis. 3. Which t-ratio listed in Table 3 represents the smallest relative difference between the pretest and 3 months?
Use a calorimeter to measure the temperature change in each of three reactions. Calculate the heat of reaction, ∆H, for the three reactions. Use the results to confirm Hess’s law. Ev al Figure 1 ua tio Na+(aq) + OH–(aq) + H+(aq) ) + Cl–(aq) → H2O(l) + Na+(aq) + Cl–(aq) ∆H3 = ? n (3) Solutions of aqueous sodium hydroxide and hydrochloric acid react to form water and aqueous sodium chloride.
Empirical formula: CH5N Steps for molecular formula: 1- Calculate the molar mass of the empirical formula. 2- Divide the known (given) molar mass by the calculated empirical formula molar mass to get a whole number 3- Multiply that whole number through subscripts of the empirical formula to obtain the molecular formula. Example CH5N 12.01 g C x 1 C= 12.01 g/mol 1.008 g H x 5 H = 5.040
(Make a rough titration first). 5. Calculate the moles and mass of acetylsalicylic acid in an aspirin tablet. Determine the mass percentage of acid in a tablet. Data collection VolumeV / cm3 | Titration trials | | | | 1 | 2 | 3 | 4 | 5 | Initial burette reading V / cm3±0.05 cm3 | 0.00 | 0.00 | 0.00 | 0.00 | 0.00 | Final burette reading V / cm3±0.05 cm3 | 13.6 | 13.9 | 14.0 | 13.9 | 14.1 | Total tire V / cm3 ±0.1 cm3 | 13.6 | 13.9 | 14.0 | 13.9 | 14.1 | Table 2 Volume of HNO3 required titrating NaOH in excess Mass of aspirin tablet ±0.001 [g] | 3.229 | 3.143 | 3.142
Adverse impact is when members of a protected class are being negatively affected at higher rate than members of the majority class. It is determined by the 45ths rule which is when the ratio for one group is less than 80% of the selection ratio for another group. The reason organizations want to avoid adverse impact is due to the fact that if adverse impact is to exist and is proven in court the organization can be sued. There are many alternatives to top down selection such as banding (uses the standard error of measurement that allows similar test scores to be grouped; Passing Scores, and the Rule of 3. Unstructured interviews are not necessarily a bad interviewing technique, the problem lies with a few components.